As much as I dislike the cover for the previous issue, it cannot hold a candle to the awfulness of the cover for All-Star Comics 65 (March/April 1977). If Vandal Savage just punched Superman, how is Superman's leg in front of Savage? Where exactly is the ground? Are Power Girl and Star-Spangled Kid on the ground, or flying? And why is the Star-Spangled Kid freaking out that way? It's not like he has been hit.
Anyway, the Levitz and Wood Justice Society story is better than the cover. Couldn't be worse. Savage brings Superman and Power Girl to an artificial planet he has created, with a kryptonite sun, just to torment and play with them, draining their power before killing them, so that he can restore his immortality. It's not completely clear how this will work, but he has a lot of cool machines, so I guess one will transfer Superman's power to him. Hawkman and the Star-Spangled Kid are later revealed to be captives on this world as well. The Flash managed to get away, and spends much of the issue travelling through time, trying to find everyone.
Green Lantern is not having a good day, either. He watches as Gotham Broadcasting Company, now bankrupt, gets all packed up and carted away. A mysterious man approaches him. I like the somewhat subtle way the villain is handled. It's possible to figure out who it is, but not likely one would guess.
Merlin is also being held a prisoner on Savage's world, and had been being mind controlled in the previous issue. Now he manages to free Hawkman. Hawkman's wings have been destroyed by Savage, but he uses his skill and familiarity with navigating in anti-gravity to get away and make it to the Star-Spangled Kid. The Kid uses his Cosmic Converter Belt to make new wings for Hawkman, and later a suit for Superman to protect him from the kryptonite sun, before rescuing Power Girl.
With the suit on, Superman is able to turn the tables on Vandal Savage, who flees into a portal taking him off his world. Savage will return four years down the road, in the pages of Action Comics, going after the Superman of Earth-1.
As the story ends Wildcat arrives at the JSA headquarters, only to be taken down by Hourman, under the control of the Icicle.
The story continues in the next issue.